A designer Bulgari gold diamond necklace worth $11,000 and other pricey jewellery are up for grabs as part of an auction of lost property found at an Australian airport.

Brisbane Airport is putting the lost items – as well as airport memorabilia – up for auction for charity.

The auction features hundreds of items left behind by the 24 million passengers who travelled through the terminals in the past year.

Despite efforts to reunite owners with their belongings, many items remain unclaimed, the airport said.

Other forgotten items like walking sticks, hundreds of pairs of sunglasses, dozens of phones and numerous pair of headphones are also on offer.

A hefty supply of laptops is also being sold, as well as a printer which appears to have been lost.

Walking frames and children’s buggies have also ended up not being claimed.

Some forgetful fliers also managed to lose pairs of sneakers and other clothes and shoes, fishing rods and surfboards.

A handful of sewing machines have also bizarrely made it to lost property, as well as medical gear like CPAP machines.

Meanwhile, special airport memorabilia including old plane seats, an Ansett lifejacket from the defunct airline and even a black box flight recorder from a plane are also being sold to the highest bidder.

“It’s always surprising and even a little bizarre to see what gets left behind by the 70,000 passengers who pass through Brisbane Airport each day,” Peter Doherty from the airport said.

“With Brisbane Airport turning 100 this year, we’ve also included some special heritage aviation items we think will attract a lot of interest.

“Where else can you pick up a row of airline seats, a black box, cockpit voice recorder or vintage life jackets with Ansett on them?”